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| author | Joerg Roedel <jroedel@suse.de> | 2020-09-07 16:15:11 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-09-07 20:45:24 +0300 |
| commit | 7af1bd822dd45a669fc178a35cc8183922333d56 (patch) | |
| tree | 616542d0ee1299c7b4a0c79b80b5fdf5810399e5 /arch/x86 | |
| parent | 172639d79977ca7b5ce6f84f6606262f4081718f (diff) | |
| download | linux-7af1bd822dd45a669fc178a35cc8183922333d56.tar.xz | |
x86/insn: Add insn_get_modrm_reg_off()
Add a function to the instruction decoder which returns the pt_regs
offset of the register specified in the reg field of the modrm byte.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-11-joro@8bytes.org
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/insn-eval.h | 1 | ||||
| -rw-r--r-- | arch/x86/lib/insn-eval.c | 23 |
2 files changed, 24 insertions, 0 deletions
diff --git a/arch/x86/include/asm/insn-eval.h b/arch/x86/include/asm/insn-eval.h index 392b4fe377f9..f748f57f1491 100644 --- a/arch/x86/include/asm/insn-eval.h +++ b/arch/x86/include/asm/insn-eval.h @@ -17,6 +17,7 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs); int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs); +int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs); unsigned long insn_get_seg_base(struct pt_regs *regs, int seg_reg_idx); int insn_get_code_seg_params(struct pt_regs *regs); int insn_fetch_from_user(struct pt_regs *regs, diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index 2323c85132cf..f20942ce76c6 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -20,6 +20,7 @@ enum reg_type { REG_TYPE_RM = 0, + REG_TYPE_REG, REG_TYPE_INDEX, REG_TYPE_BASE, }; @@ -439,6 +440,13 @@ static int get_reg_offset(struct insn *insn, struct pt_regs *regs, regno += 8; break; + case REG_TYPE_REG: + regno = X86_MODRM_REG(insn->modrm.value); + + if (X86_REX_R(insn->rex_prefix.value)) + regno += 8; + break; + case REG_TYPE_INDEX: regno = X86_SIB_INDEX(insn->sib.value); if (X86_REX_X(insn->rex_prefix.value)) @@ -808,6 +816,21 @@ int insn_get_modrm_rm_off(struct insn *insn, struct pt_regs *regs) } /** + * insn_get_modrm_reg_off() - Obtain register in reg part of the ModRM byte + * @insn: Instruction containing the ModRM byte + * @regs: Register values as seen when entering kernel mode + * + * Returns: + * + * The register indicated by the reg part of the ModRM byte. The + * register is obtained as an offset from the base of pt_regs. + */ +int insn_get_modrm_reg_off(struct insn *insn, struct pt_regs *regs) +{ + return get_reg_offset(insn, regs, REG_TYPE_REG); +} + +/** * get_seg_base_limit() - obtain base address and limit of a segment * @insn: Instruction. Must be valid. * @regs: Register values as seen when entering kernel mode |